A 11/2" RMC nipple with three conductors can be filled to an area of ___ square inches.

• A. 0.98
• B. 1.07
• C. 1.34
• D. 1.243

Answer: (D)

Conduit fill sets how much cross-sectional area inside a raceway or nipple can be occupied by conductors. The code uses a table that ties the number of conductors and the conduit size to a maximum allowable fill area, not simply the sum of each conductor’s insulation area. For a 1-1/2 inch rigid metal conduit with three conductors, the standard table specifies a maximum fill area of 1.243 square inches. The other numbers don’t match the table’s permissible fill for this size-and-count configuration, so 1.243 in^2 is the correct value. This reflects the packing and insulation thickness allowances the code accounts for, ensuring enough space for heat dissipation and ease of pulling conductors.